1. Technical Field
The present invention generally relates to an image formation apparatus and an image formation method. In particular, the invention can be suitably applied to an image formation apparatus that uses a liquid developer containing toner particles and carrier liquid.
2. Related Art
As an example of an image formation apparatus that uses a liquid developer, an apparatus that is provided with the following components is disclosed in JP-A-2001-166611; the components include a latent image carrier (e.g., photosensitive drum) on which a latent image is formed, a developing section (e.g., developing device) that develops the latent image with the use of a liquid developer to form a developed image on the latent image carrier, a primary image transfer member that transfers the developed image formed on the latent image carrier onto the image-carrying surface of a transfer member (e.g., intermediary image transfer belt) that moves cyclically for primary image transfer, and a secondary image transfer roller that can be brought into contact with the image-carrying surface of the transfer member with a recording target medium being pinched therebetween to further transfer the image transferred to the image-carrying surface onto the recording target medium for secondary image transfer (refer to FIG. 1). Such an image formation apparatus of related art has a plurality of members each of which has a surface for retaining a liquid developer and moves cyclically. Examples of these members are the latent image carriers, primary image transfer rollers, the secondary image transfer roller, and the like. These members may be hereinafter referred to as “retaining members”. A contact edge of a cleaning blade is placed in contact with the retaining surface of a retaining member. The cleaning blade wipes a liquid developer that remains on the retaining surface off for removing the liquid developer from the retaining surface.
Some retaining members can be brought into contact with the retaining surface of another retaining member or distanced from the retaining surface thereof. For example, during the operation of an image formation apparatus, a secondary image transfer roller is set at a contact position where the outer circumferential surface of the secondary image transfer roller, which is the retaining surface of the secondary image transfer roller, is in contact with the image-carrying surface of an intermediary image transfer belt (transfer member), which is the retaining surface of the intermediary image transfer belt. On the other hand, for example, when the operation of an image formation apparatus is suspended for a while, the outer circumferential surface of the secondary image transfer roller is distanced from the image-carrying surface of the intermediary image transfer belt. The retaining member of the related art, for example, the secondary image transfer roller, has the following problems.
A cleaning blade that is urged toward and in contact with a secondary image transfer roller for cleaning the secondary image transfer roller has an end face (which may be hereinafter referred to as a “contact-side end face”) and a surface that faces toward the secondary image transfer roller. An edge is formed at a region where the contact-side end face and the surface facing toward the secondary image transfer roller meet with each other. When the secondary image transfer roller is continuously distanced from an intermediary image transfer belt (transfer member) for a while, a liquid developer that gathers at a space between the outer circumferential surface of the secondary image transfer roller and the contact-side end face, which may be hereinafter referred to as a “reservoir space” or “reservoir”, could drip from the reservoir space to stain inner components of the image formation apparatus.
As another problem, when an image formation apparatus is driven with a secondary image transfer roller being in contact with an intermediary image transfer belt when a sufficient amount of a liquid container is not present in a reservoir space after the setting of the secondary image transfer roller at a non-contact position where the secondary image transfer roller is distanced from the intermediary image transfer belt for a while, friction may arise between a cleaning blade and the secondary image transfer roller. The friction might cause the squeaking of the cleaning blade. Furthermore, when friction arises between the cleaning blade and the secondary image transfer roller, a driving torque of the secondary image transfer roller increases, which might result in unstable driving operation.